1. Field of the Invention
The invention relates to a drainage construction of a waterproof cover of an electrical connection box and is particularly designed to prevent water from entering a junction box for an automobile vehicle.
2. Description of the Related Art
Some junction boxes for automotive vehicles often are mounted below ducts of air conditioners in the vehicle. Waterdrops are likely to accumulate on the ducts and could drop down from the ducts and onto the junction boxes or wires that communicate with the junction boxes. These waterdrops could enter water-free areas of the junction boxes, such as the connector accommodating portions. Accordingly, junction boxes and related parts should be designed to prevent the entry of water.
FIG. 9 shows a junction box 1 with a casing and a connector accommodating portion 1a in an upper surface of the casing. A connector 2 is provided at an end of a wiring harness W/H and is fit into the connector accommodating portion 1a. A waterproof sheet 3 is adhered in a position to prevent waterdrops from entering the connector accommodating portion 1a. 
The above-described waterproof sheet 3 may deform during use into a shape that causes the waterdrops to flow in unexpected directions. Thus, waterdrops that fall from the duct and onto the waterproof sheet 3 may run along the rear surface of the waterproof sheet 3 or otherwise flow from the sheet 3 into the water-free areas. Further, water that falls on the waterproof sheet 3 may stay on the sheet 3 without immediately running off the sheet 3. In such a case, the accumulated water may run down at once due to an unexpected deformation of the waterproof sheet 3 and may be scattered in the water-free areas.
An operator may forget to adhere the waterproof sheet 3 after the connector 2 is fit into the connector accommodating portion 1a of the junction box 1. Thus, water may enter the connector accommodating portion 1a or other water-free areas of the junction box 1.
The present invention was developed in view of the above problems and an object thereof is to drain water reliably for preventing water from entering water-free areas of an electrical connection box, and to ensure that forgetfulness of an operator cannot lead to intrusion of water.
The invention is directed to a drainage construction of a waterproof or waterdeflecting cover of an electrical connection box. The construction comprises a waterproof or waterdeflecting cover to be provided on an upper surface of a casing of an electrical connection box. The waterproof cover comprises at least one recess for at least temporarily collecting or deviating water that falls down on the outer surface of the waterproof cover. At least one water-diverting portion is formed by raising a portion of the recess, and by providing a dropping portion. Waterdrops that fall down on the outer surface of the waterproof cover stay at least temporarily in the recess and then drain along the dropping portion. Accordingly, a drainage path is set intentionally for the waterdrops. Therefore, waterdrops that fall down from the outer surface of the waterproof cover are prevented from dropping down onto the water-free areas of the electrical connection box.
At least one water collection causing portion may project up at another location. The water collection causing portion may comprise at least one rib that projects up the other end of the recess.
The dropping portion preferably is below the water collection causing portion.
Waterdrops that fall down on the outer surface of the waterproof cover preferably are caused to stay at least temporarily in the recess and are caused to be drained along the dropping portion when the water level exceeds the height of the rib or other water collection causing portion.
More specifically, waterdrops are collected first in the recess on the outer surface of the waterproof cover. The water-diverting portion preferably is raised at one side of the recess with respect to the longitudinal direction. Thus, water in the recess is introduced to the side that has the dropping portion.
The rib or other water collection causing portion projects up at the other side to dam the water in the recess and to cause the water to stay at least temporarily in the recess. Thus, the water can be caused to vaporize preferably without being drained out of the cover in the case of a small quantity of waterdrops.
Water in the recess may reach a level that exceeds the height of the rib or other water collection causing portion. However, such water can be drained reliably to a place other than the water-free areas of the electrical connection box by running down on the dropping portion that projects below the rib or other water collection causing portion.
A groove preferably is formed vertically in the dropping portion of the waterproof cover for guiding the water. Thus, water that drops down along the dropping portion can be guided reliably to an intended place along the groove.
The waterproof cover preferably is mounted rotatably or pivotably on a bracket for fixing the electrical connection box to a vehicle body to cover the upper surface of the casing. A first connector preferably is fit into a connector accommodating portion in the upper surface of the casing with the waterproof cover rotated to a standby position that preferably is toward a side surface of the casing. Thus, the cover substantially blocks entry of a connector into a connector accommodating portion in the side surface of the casing. A second connector may be fit into the connector accommodating portion in the side surface of the casing when the waterproof cover is rotated to a proper position that preferably is toward the upper surface of the casing. With this construction, the connector accommodating portion in the side surface of the casing is covered at least partly by the waterproof cover when the first connector is fit into the connector accommodating portion in the upper surface of the casing. Thus, the second connector cannot be fit into the connector accommodating portion unless and until the waterproof cover is rotated to the proper position.
A slanted guide portion preferably projects below the dropping portion, and a bottom end of the slanted guide portion is more outward than water-free areas of the electrical connection box.
Design factors may prevent the dropping portion of the waterproof cover from being more outward than the water-free areas of the electrical connection box. However, the slanted guide portion in the standby state is below the dropping portion and drains water that drops down from the dropping portion outside the water-free areas of the electrical connection box.
The slanted guide portion may be formed integrally at the waterproof cover if permitted by design parameters.
These and other objects, features and advantages of the present invention will become more apparent upon reading of the following detailed description of preferred embodiments and accompanying drawings. It should be understood that even though embodiments are separately described, single features thereof may be combined to additional embodiments.